Disposable absorbent articles, e.g., diapers, catamenial pads, panty liners, shields, etc., frequently make use of a liquid absorbent core located between a top sheet and a back sheet. The top sheet is commonly formed of a material which is pervious to body fluids, e.g., urine, to promote the transfer of such fluids into the core with minimal fluid retention by the top sheet. The back-sheet is commonly formed of a liquid impervious or hydrophobic material to form a barrier wall so that any fluid absorbed by the article cannot escape out the back-sheet. In many cases, a fluid “acquisition,” “surge” or “transfer” layer is located between the top sheet and the core to facilitate the transference of body fluid(s) into the core.
In co-pending U.S. patent application Ser. No. 09/439,793, filed on Nov. 12, 1999, entitled Absorbent Article with Improved Fluid Acquisition System, which is assigned to the same assignee as this invention, namely, Tyco Healthcare Retail Group, Inc., there is disclosed an absorbent article, e.g., a diaper, arranged to be worn by a wearer to trap and collect fluid waste products, e.g., urine, of the wearer. The article has a flexible chassis and plural tabs for holding the diaper in place on the wearer. The chassis is made up of a top sheet, a fluid acquisition system, and a fluid absorbent core. The top sheet is formed of a fluid pervious material, e.g., a fibrous material. The core includes fast acting fluid absorbing material, e.g., fluff, and a slow acting fluid absorbing and retaining material, e.g., SAP. The fluid acquisition system comprises a first fluid acquisition layer formed of apertured polymeric, e.g., three dimensional, film and a second fluid acquisition layer, e.g., a fibrous material, secured together and located between the top sheet and the core, with the first fluid acquisition layer facing the top sheet and the second fluid acquisition layer facing the core. The fluid acquisition system serves to facilitate the transference of fluid into the core, e.g., spread out the fluid over the core and providing it to the core at a rate at which the materials of the core can accommodate.
In another co-pending U.S. patent application Ser. No. 09/562,541, filed on May 2, 2000, entitled Absorbent Article with Improved Fluid Acquisition System And Method Of Making The Same, which is a Continuation-In-Part of Ser. No. 09/439,793, filed on Nov. 12, 1999 and is also assigned to the same assignee as this invention, there is disclosed an absorbent article with a dual layer fluid acquisition system. That application discloses a disposable absorbent article, e.g., a diaper, and a method of making it. The article has a flexible chassis and plural tabs for holding the diaper in place on the wearer. The chassis is made up of a top sheet, a fluid acquisition system, and a fluid absorbent core. The top sheet is formed of a fluid pervious material, e.g., a fibrous material. The core includes fast acting fluid absorbing material, e.g., fluff, and a slow acting fluid absorbing and retaining material, e.g., SAP. The fluid acquisition system comprises a first fluid acquisition layer formed of apertured polymeric, e.g., three dimensional film, and a second fluid acquisition layer, e.g., a fibrous material, secured together and located between the top sheet and the core, with the first fluid acquisition layer facing the top sheet and the second fluid acquisition layer facing the core. The fluid acquisition system serves to facilitate the transference of fluid into the core, e.g., spread out the fluid over the core and providing it to the core at a rate at which the materials of the core can accommodate. The first and second acquisition layers may be joined or bonded together via various techniques, such as by adhesives, ultrasonic bonding, heat sealing, hot knife-slitting, hydroentanglement, physical stitching or sewing, etc.
The patent literature includes other patents relating to absorbent articles with fluid acquisition systems. For example, U.S. Pat. No. 5,300,054 (Feist et al.) is directed to an absorbent article, such as a diaper, which has a rapid acquiring wrapped multiple layer absorbent body in an absorbent core. The absorbent article includes a liquid pervious top sheet, a liquid impervious back sheet, and an absorbent core position between the top sheet and the back sheet. The absorbent core comprises a multiple layer absorbent body having an acquisition layer. A fluid transporting wrapping at least partially surrounds the multiple layer absorbent body to form a wrapped multiple layer absorbent body. See FIG. 9. As shown in this cross-section, the multiple layer absorbent core is wrapped in a low density wrapping of material that is capable of transporting fluids. The wrapped multiple layer absorbent body overlies a storage layer material, such as a layer of air-felt. The high-loft wrapping of material serves as an additional acquisition/distribution layer to transport exudates to the layer of air-felt. The double layer of the wrapping is located above the air-felt storage layer, i.e., the wrapping does not surround the storage layer over which the double layer resides.
U.S. Pat. No. 5,752,945 (Mosley et al.) discloses an absorbent article, such as a diaper, that has an absorbing core and an outer porous cover sheet to allow transfer of liquids through the cover sheet and into the core. A liquid transfer sheet, in the form of a non-woven fabric, is located between the cover sheet and the core. The transfer sheet has at least two layers, with the layer facing the cover sheet having relatively coarse fibers and the layer facing the core having relatively fine fibers. This arrangement allows for more efficient transfer of liquids into the core, while minimizing wetback.
U.S. Pat. No. 5,762,642 (Coles, et al.) discloses an absorbent article having a liquid pervious top sheet, a liquid impervious back sheet and an absorbent core interposed between the top sheet and the back sheet. As can be seen in FIGS. 4A and 4B, the core is wrapped with folded tissue which overlap each other. The overlapped portion is on the back sheet side of the article.
U.S. Pat. No. 6,066,775 (Bachar) is directed to a method of manufacturing an absorbent core for a diaper. Here, a non-woven sheet is provided which includes three coextensive longitudinal trisections, a center trisection, and two outer trisections. The non-woven sheet further includes three coextensive latitudinal trisections. A super-absorbent polymer is applied to two of the latitudinal trisections. The two outer longitudinal trisections are folded over the super-absorbent polymer in a triple fold so as to form a sandwiched absorbent core including a bottom layer of the woven sheet, layer of the super absorbent polymer, and two upper layers of the non-woven sheet. The desired goal of this invention is to place 95% of the total super absorbent polymer in the front and crotch portions and 5% in the rear portion of the article.
U.S. Pat. No. 6,103,953 (Cree, et al.) is directed to an absorbent article, such as a diaper, having fused layers. The article includes a liquid pervious apertured film top sheet, a liquid impervious back sheet, an absorbent core, and a woven or unwoven acquisition layer. The acquisition layer may be a double, z-folded sheet.
U.S. Pat. No. 3,968,798 (Hokanson) discloses a disposable incontinent pad, such as a diaper, which includes a fluid absorbent matrix with a facing sheet, and a water impervious backing sheet having the matrix therebetween. The article has a C-fold configuration with the backing sheet overlapping the fold lines onto the facing sheets such that, when the pad is worn, it is resistant to lateral run-off of body fluid.
Other examples of prior art acquisition layers are disclosed in U.S. Pat. No. 4,988,344 (Reising et al.), U.S. Pat. No. 4,994,037 (Bernardin), U.S. Pat. No. 5,294,478 (Wanek et al.), U.S. Pat. No. 5,300,054 (Feist et al.), U.S. Pat. No. 5,304,161 (Noel et al.), U.S. Pat. No. 5,387,208 (Ashton et al.), U.S. Pat. No. 5,460,622 (Dragoo et al.), U.S. Pat. No. 5,486,167 (Dragoo et al.), U.S. Pat. No. 5,520,673 (Yarbrough et al.), U.S. Pat. No. 5,522,809 (Larsonneur), U.S. Pat. No. 5,558,655 (Jezzi et al.), U.S. Pat. No. 5,591,149 (Cree et al.), U.S. Pat. No. 5,607,414 (Richards et al.), U.S. Pat. No. 5,609,588 (DiPalma et al.), U.S. Pat. No. 5,730,737 (Widlund et al.), U.S. Pat. No. 5,752,945 (Mosley et al.), U.S. Pat. No. 5,833,678 (Ashton et al.), U.S. Pat. No. 5,843,055 (Seger), U.S. Pat. No. 5,855,572 (Schmidt), U.S. Pat. No. 5,895,379 (Litchholt et al.), and U.S. Pat. No. 5,906,602 (Weber et al.).
Examples of commercially available materials used for acquisition layers in disposable absorbent articles are through-air bond staple fibers, adhesively bonded staple fibers, and thermally point bonded staple fibers. Moreover, various absorbent articles which are commercially available have made use of various layers of materials, some of which make up an acquisition system. For example, sanitary pads made by Tyco Healthcare Retail Group, Inc. and sold under the trademark EVERYDAY PANTILINER have included a top sheet formed of a fibrous material over the marginal edges of the pad, but not over the intake or “target” zone (i.e., the area at which the body fluid(s) gain(s) ingress into the absorbent article), a three dimensional apertured film forming the top layer of the intake/target zone, a fluid acquisition layer formed of a fibrous material (non-woven) web, and a core formed of an air laid web containing super absorbent material. Other pads in the form of Ultra Thins are also made by Tyco Healthcare Retail Group, Inc. and sold under trademark FRESH TIMES have included a top sheet formed of an apertured film, an air-laid acquisition layer and a core formed of a combination of air-laid and SAP or an air laid super absorbent material. Still other pads in the form of Contour Maxi pads are made by Tyco Healthcare, Inc. and sold under the trademark FRESH TIMES have included a top sheet formed of an apertured film and a core formed fluff. Still other pads in the form of Maxi pads are made by Tyco Healthcare Retail Group, Inc. and sold under the trademark FRESH TIMES have included a top sheet formed of a fibrous material, a tissue fluid acquisition layer and a core formed of fluff. Diapers made by Tyco Healthcare Retail Group, Inc. and sold under the trademark HAPPIES have included a non-woven top sheet, a through-air-bonded (or non-woven) acquisition layer, a tissue layer, and an absorbent core made of fluff and SAP.
While the aforementioned absorbent articles and/or fluid acquisition systems are suitable for their intended purposes, they still leave something to be desired from the standpoints of simplicity of construction and ease and economy of manufacture.